Asphalt shingles have been manufactured for many years by impregnating a web of mat, generally of fiberglass material, with a bitumen, such as asphalt, and applying granules of desired color and/or contrast to that surface of the shingle that would be the upper surface of the shingle when the shingle is in an installed condition on a roof. Generally, the shingle is constructed to have multiple tabs separated by slots cut inward of the shingle from the lower edges of the tabs, to leave the tabs spaced-apart relative to each other. Sometimes the granules in the headlap or butt portion of the shingle; i.e., above the tabs, are of a darker, less expensive nature, because generally the headlap portion of the shingle will be covered when shingles are laid up on a roof in courses, with shingles in a next-overlying course covering headlap portions of shingles in a next underlying course, and with each overlying course of shingles being staggered longitudinally (leftward or rightward) relative to the next underlying course of shingles.
It is also known in the shingle/roofing art that it is the tab portions of shingles that are weather-exposed in the installed condition, and thereby it is the tabs of shingles that can be lifted up by wind conditions, and that if such tabs are bent upwardly a sufficient amount, they can crack and, if the wind conditions are severe enough, can be blown off the roof.
Accordingly, it is known to provide wind resistance for tabs of shingles that are installed on a roof. Such resistance is usually effected by application of adhesive beneath the tab portions of shingles, generally at the lower ends of the tabs, so that the lower ends of the tabs are adhesively secured to headlap portions of shingles in a next-underlying course of field shingles of a roof covering.